During endodontic therapy it is customary to maintain the field aseptic by a dam consisting of a flexible web of rubber stretched in place over a frame lying against or adjacent the patient's face. A hole is formed in the dam and a clasp is secured to the dam. The clasp in turn is clamped to the tooth being operated on.
In the course of such therapy it may be necessary to take one or more roentgenograms. The dam must then be temporarily moved aside to allow placement of the roentgenogram in the oral cavity. The dam should be moved aside in such manner that risk of contamination of the field and possible distortion of the roentgenogram are minimized. Furthermore, the procedure should be carried out with the least loss of time and discomfort to the patient.
It is an object of the present invention to provide a holder for a flexible dam for the purpose stated, said holder comprising sections movably connected together in a manner such that a part of the dam, e.g. one-half, may be quickly and easily displaced from the mouth-covering position when it is desired to take a roentgenogram, while retaining the other part of the dam in sterile-maintaining position. However, if the position of the film holder with respect to the dam holder is such that partial overlap occurs, the holder may be fabricated of a plastics composition which is transparent to X-rays.
It is a further object of the present invention to provide a dam holder for the stated purpose in which the dam remains secured to the frame when the latter is moved to an inactive position. This not only materially reduces the possibility of contaminating the sterile field during taking of roentgenograms, but facilitates manipulation of the frame.
It is a still further object of the invention to provide a holder in the form of a frame that is relatively small in size and compact as compared to frames heretofore used, and wherein the taking of roentgenograms is greatly facilitated with minimum discomfort to the patient or loss of time for the operator.
In accordance with the principles of the invention, a frame is desirably fabricated in the form of a U of molded plastics composition which is transparent to X-rays. The legs or sides of the frame carry a number of arrow-shaped pins, also desirably transparent to X-rays, by means of which the dam is secured to the frame. The pointed head of the pins permits the dam to be readily attached to the frame while preventing inadvertent slippage. The bight of the frame is divided into two symmetrical halves hingedly connected together at the mid-plane thereof. The hinge axis is substantially parallel to the sides of the frame in order that, when the dam is in operating position on the frame and clamped to the tooth being treated, either the left or right hand part of the frame can be swung about the hinge axis to allow sufficient access to the oral cavity for placement of a roentgenogram.
In another embodiment the frame is molded in one piece with the two halves pivotally joined by a so-called "living hinge". In this molded embodiment the cost of the device is considerably reduced, is lighter in weight, and there are no mechanically articulated connections which may jam or break. Furthermore, the inclusion of a resilient snap latch, the parts of which are integrally molded with the two halves of the frame enables the frame to be readily positioned with one leg folded back when X-rays are being taken.